Conventionally, there is a tracking processing device that, for monitoring moving objects such as persons and vehicles over a wide area, acquires images captured by cameras set up at multiple locations where moving objects pass and tracks the moving objects in each camera or across the multiple cameras by use of the captured images. In the tracking of the moving objects by this tracking processing device, an occlusion (namely, a state in which a target to be tracked is hidden by another object present in front of the target to be tracked in each camera view) may occur depending on the positional relationship between the camera and a moving object (target to be tracked), and as a result, it may become difficult to perform the tracking of the moving object based on the captured images.
To address such a problem, technologies for reducing the influence of an occlusion or the like and thereby enabling highly accurate tracking have been developed. For example, a tracking processing device is known which includes multiple cameras for capturing images of a monitored space from mutually different points of view, sets multiple assumptions each representing a combination of a predicted position of the moving object at the current time and a monitoring camera, and obtains the position of the moving object at the current time on the basis of the assumption with the highest likelihood (namely, the assumption suitable for the tracking of the moving object) (see Patent Document 1).